Calculation of Volterra Kernels for Solutions of Nonlinear Differential Equations. - Erik G. F. Thomas; J. Leo van Hemmen; Werner M. Kistler (SIAM J. Appl. Math., 2000)

Time-autonomy versus time-controllability. - Amol J. Sasane; Erik G. F. Thomas; Jan C. Willems (Syst. Control. Lett., 2002)